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Crotalaria retusa


Crotalaria retusa L.

Family Name: Fabaceae (Leguminosae)
Synonyms: Crotalaria tunguensis
Common Name: Rattleweed, Shak-Shak, Rattlebox, Wedge-leaf Rattlebox, 吊裙草, 凹叶野百合, 洛苛草


Family Name
Genus Epithet
Species Epithet
Name Authority
Name Status (botanical)
Common Names

Classifications and Characteristics

Plant Division Angiosperms (Flowering Seed Plants) (Dicotyledon)
Plant Growth Form Herbaceous Plant
Lifespan (in Singapore) Annual
Mode of Nutrition Autotrophic
Maximum Height 1 m to 2 m


Native Distribution Africa, Pantropical
Native Habitat Terrestrial
Preferred Climate Zone Tropical
Local Conservation Status Cryptogenic

Description and Ethnobotany

Growth Form Herbaceous plant with erect growth habit, can grow up to 1.2 - 1.5 m tall.
Foliage Simple leaves, obovate, having a rounded leaf tip and a wedge-shaped leaf base (3.3 - 9.2 cm long, 1 - 3.8 cm wide). They are sessile, spirally arranged and have an entire leaf margin.
Stems Stem is ridged and velvety with short hairs.
Flowers Bright yellow flower consists of 1 large triangular petal hanging over 2 smaller petals that are curled upwards like a hook (1.7 - 2.4 cm long). Flowers are arranged in terminal spike inflorescences located at the branch tips (27 cm long).
Fruit Dry, hairless, cylindrical fruit is known as a pod (3 - 4 cm long). Pod colour changes from greenish to dark brown to black when mature. Shaking a mature pod produces a rattle sound, because the seeds get loose inside.
Habitat Occurs along seashores and dry coastal areas.
Cultivation This species should be planted in fertile, well-draining soil.

Landscaping Features

Landscaping This species is planted for its bright yellow flowers. The spirally arranged leaves around an erect stem produces an attractive, symmetrical form. It can be used as a hedge or screen.
Desirable Plant Features Ornamental Flowers
Landscape Uses Parks & Gardens

Fauna, Pollination and Dispersal

Fauna Pollination Dispersal Associated Fauna Caterpillar Food Plant (Associated with: Lampides boeticus (Linnaeus, 1767)), Bee-Attracting
Pollination Method(s) Biotic (Fauna) (Insects (Butterfly, Moth))

Plant Care and Propagation

Light Preference Full Sun
Water Preference Moderate Water
Plant Growth Rate Fast
Rootzone Tolerance Moist Soils, Well-Drained Soils
Propagation Method Remarks Propagate by seed or stem cuttings. Seeds should be collected from mature pods that were allowed to dry on the plant. Sow seeds immediately, because they quickly lose viability.


Mature Foliage Colour(s) Green
Foliar Type Simple / Unifoliate
Foliar Attachment to Stem Sessile
Foliar Margin Entire
Leaf Area Index (LAI) for Green Plot Ratio 4.5 (Shrub & Groundcover - Dicot)

Floral (Angiosperm)

Flower & Plant Sexuality Bisexual Flowers
Flower Colour(s) Yellow / Golden
Flower Grouping Cluster / Inflorescence
Flower Symmetry Bilateral
Inflorescence Type Spike

Fruit, Seed and Spore

Mature Fruit Colour(s) Black
Fruit Classification Simple Fruit
Fruit Type Dehiscent Dry Fruit , Legume / Pod
Mature Seed Colour(s) Brown
Mature Seed Texture(s) Smooth
Seed Quantity Per Fruit Numerous (>20)

Image Repository



Master ID 596
Species ID 1891
Flora Disclaimer The information in this website has been compiled from reliable sources, such as reference works on medicinal plants. It is not a substitute for medical advice or treatment and NParks does not purport to provide any medical advice. Readers should always consult his/her physician before using or consuming a plant for medicinal purposes.
Species record last updated on: 05 August 2023.